Abstract: The invention relates to a method for changing a welding process during a welding operation, wherein the change is carried out from a welding process that was conducted to a subsequent welding process during a short circuit between a melting welding wire and a workpiece, and to a method for applying heat prior to a welding operation. In order to achieve a welding process with high process stability, it is provided that, upon detecting the short circuit of the welding process that is conducted, the welding wire (9) is still moved for a defined duration (32) in the movement direction and subsequently stopped, depending on a threshold value (34) of the welding current (I) of the subsequent welding process, whereupon upon reaching the threshold value (34) of the welding current (I), the welding wire (9) is moved in the opposite direction in order to start the subsequent welding process.

Abstract: A welding method of carrying out an alternating current arc welding by switching polarities of a voltage applied between a wire and workpieces when weld-connecting the workpieces to each other by use of the wire, the workpieces including an aluminum cast material and an aluminum wrought material. In the welding method, the alternating current arc welding is carried out in a way to satisfy |B|/(A+|B|)?0.128 where A denotes an integrated value of an electric current over a time for which the polarity of the wire is positive, and B denotes an integrated value of an electric current over a time for which the polarity of the wire is negative; and thereby an amount of heat input into the aluminum cast material during the welding is set at not more than 67.8 J/mm2.

Abstract: A wire feeding speed is decreased to a level lower than a base wire feeding speed in a short-circuiting period, and set to the base wire feeding speed in an arcing period. During the arcing period, a welding current is increased to a predetermined peak value by means of current control from the start of arcing to a first predetermined time, the welding current is then supplied with a welding voltage, a source voltage of which is controlled constant, from the first predetermined time to a second predetermined time, and the welding current is decreased to a predetermined base current by means of current control from the second predetermined time until the end of the arcing period.

Abstract: A welding device includes a welding torch, a memory, a power supply, an input section, a selector, and a controller. The welding torch includes a welding tip having a feeder for supplying electric power to a welding wire. The memory stores a plurality of welding conditions in which a feeder-work-piece to be welded distance is associated with at least one a length of the wire supplied per unit time, a weight of the wire supplied per unit time, and a set electric current. The power supply supplies electric power between the wire and the work-piece. The input section receives an input of a set value of a feeder-work-piece distance. The selector selects one of the welding conditions stored in the memory based on the set value. The controller controls the power supply based on the welding condition selected by the selector.

Abstract: A spark gap device is described such as for use in welding systems. The device receives a high voltage, low current input signal and produces high frequency waveform output. The device includes one or more toroidal members surrounding a rod-like member with an annular gap therebetween. When the input signal is applied to the device, arcs are established in the gap between the toroidal members and the rod-like member, producing the high frequency output. Erosion and loci of arcs between the toroidal members and the rod-like member are distributed, resulting in extended life of the assembly. The gaps are also shielded from contaminants and moisture by an insolative body that maintains the toroidal members and the rod-like member in place with respect to one another.

Abstract: A base metal composed of a plurality of metallic materials having an oxygen content of 10 ppm is first preheated partly or overall. Then AC (alternating current) current is made to pass through the preheated base metal and an electrode so as to generate an arc for welding the metallic materials. The waveform of the current is changed with time between a peak current value and a base current value excluding a current of zero value only in one of plus and minus polarity sides of the current. A current ratio defined by dividing a current amplitude between the peak and base current values by a current average of the alternating current is a range of 0.5 to 2.0. The alternating current has a frequency of 500 Hz or higher.

Abstract: A pulsed waveform welding operation is implemented by reference to a commanded wire feed speed set by an operator. The wire feed speed is set on a wire feeder, and a signal representative of the commanded wire feed speed is applied to a power supply. The power supply control circuitry references a look-up table in which pulsed waveform parameters are provided based upon wire feed speed. The parameters may include multiple parameters such as pulse frequency, peak current, background current, and current ramp rates. The control circuitry commands power conversion circuitry to generate the commanded waveform as a function of the commanded wire feed speed.

Abstract: A method of AC welding that includes the step of supplying AC current with a given waveform from a power source to an advancing electrode and workpiece. The AC current is used to melt the electrode and to thereby deposit metal from the electrode onto the workpiece. The electrode includes a particulate arc stabilizing compound. The particulate arc stabilizing compound includes sodium and titanium dioxide. The particulate arc stabilizing compound constitutes over 20% by weight of the core of the electrode.

Abstract: A robot welding controller and a robot welding control. It comprises a robot having a welding torch at its tip, a robot controller, a wire feeder, and a welding electric power. It performs welding by moving the welding torch on the basis of a commanded welding line. A contact detecting section detects contact of the wire and the base material. A feed direction switching section switches feed directions of the wire. An arc generation detecting section detects that an arc is generated between the wire and the base material. A waveform control section controls electric power waveforms of plural shapes applied between the wire and the base material. A welding sequence section controls the operations of the contact detecting section, the feed direction switching section, the arc generation detecting section and the waveform control section in block.

Abstract: A method and apparatus for welding include initiating a pulse welding process includes initiating a welding arc by providing CC type welding power, maintaining the arc by providing CV type power. Then, pulse type welding power is provided. The method and system can be used to start short circuit, or other welding processes by providing short circuit power, or welding power of a given mode, instead of providing pulse power. Also, in one alternative, a method and system of initiating a pulse, short circuit, or given welding process includes initiating a welding arc by providing CC type welding power at least until a pseudo-equilibrium for the arc is established. Then, providing welding power in a pulse, short circuit, or the given mode.

Abstract: A welding current controlling method is provided for an arc welding process using a consumable electrode and including an alternate repetition of a short-circuiting state and an arc generating state occurring between the consumable electrode and a base material. In the method, a neck detection is performed for the molten electrode in the short-circuiting period of time to determine if a new arc is established between the consumable electrode and the base material. Upon detection of the neck, the welding current is sharply decreased. After the new arc is established, the welding current is increased from a low level to a high level with a predetermined inclination selected for reducing vibration to the molten pool.

Abstract: The invention provides a welding system capable of freely controlling the dispersion and concentration of arc heat over the groove face with an extreamly narrow gap and a high strength and high quality welded joint structure which is formed by this welding system and which is capable of preventing softening/hardening of the structure, the lowering of the toughness thereof and the generation of a crack. According to the welding system, the melting rate of a welding wire is controlled relative to the welding wire feeding rate by changing the characteristic of an arc current so that the range of behavior and the transfer rate of the arc pole (the arc generating main point at a groove surface) are controlled. Further, the welded joint structure consists of a high strength steel having a superfine grain structure with a carbon equivalent of as low as less than 0.

Abstract: Methods and systems for creating and controlling an AC output for welding, plasma cutting or heating are provided. One embodiment of the present disclosure achieves a desired square wave AC output and reduces the number of circuit components needed by combining components of a buck converter and a full bridge inverter. Current flow paths through a power control circuit that are generated via switching of transistors in the circuit on and off are provided. In one embodiment, a pulse width modulation leg, which controls the level of current flow through an inductor, is provided. Certain embodiments include a bidirectional buck converter that converts an unregulated DC flow to a regulated DC flow through an inductor. In one embodiment, a steering leg is provided, which controls a direction of current flow through the inductor. Additionally, an output clamp circuit, which suppresses the parasitic load inductance during polarity reversal is provided.

Abstract: A welding system for performing a short arc welding process between a advancing wire electrode and a workpiece. The system comprises a power source with a controller for creating a current pulse introducing energy into the electrode to melt the end of the electrode and a low current quiescent metal transfer section following the end of the melting pulse during which the melted electrode short circuits against the workpiece; a timer to measure the actual time between the end of the pulse and the short circuit; a device for setting a desired time from the pulse to the short circuit; a circuit to create a corrective signal based upon the difference between the actual time and the desired time; and, a circuit responsive to the corrective signal to control a given parameter of the current pulse.

Abstract: A consumable electrode type arc welding method for generating arc between a plate-shaped work and a welding wire by a mixed shield gas including argon gas to weld the plate-shaped work, includes: making a state of reverse polarity in which the polarity of the welding wire is positive at the welding start time, and switching at least once to a state of positive polarity in which the polarity of the welding wire is negative.

Abstract: A modified phase shift scheme that provides the minimum on-time and regulation benefits of the conventional phase shift method with the reduced circulating current benefits of the traditional PWM control. A welding machine comprises an inverter operatively connected to a controller, wherein the controller controls a welding process of the welding machine using modified phase shifted switching of the inverter.

Abstract: A method of performing polarity switching short circuiting arc welding is provided. In the arc welding, a welding wire is fed at a constant feeding rate, a short circuiting state and a arcing state appear repeatedly between the welding wire and a base metal, and the output polarity of a welding power source is switched in accordance with a polarity switching signal for performing electrode positive welding and electrode negative welding. In accordance with the method, the welding current is reduced during a predetermined short circuit initial period, when a first arc is formed after the polarity switching signal changes. Then, the output polarity of the welding power source is changed when the short circuit initial period has lapsed. Further, the welding current is increased for terminating the arc forming between the welding wire and the base metal.

Abstract: A tandem pulse arc welding control apparatus includes a voltage detector; a voltage setting unit; a pulse-peak-current-reference-value setting circuit; a pulse-base-current-reference-value setting circuit; an error amplifier that calculates a pulse-peak-current variation value and a pulse-base-current variation value; an adder that calculates a pulse-peak-current value; an adder that calculates a pulse-base-current value; a pulse-waveform selection circuit that outputs the pulse-peak-current value in a pulse peak period, and that outputs the pulse-base-current value in a pulse base period; and an output control circuit that controls a current value for a second welding wire. Because an appropriate welding voltage can be obtained with this configuration, a high welding quality can be realized.

Abstract: A welding power supply includes a user interface that allows the operator to adjust one or more welding parameters comprising a welding sequence for a welding process. The user interface may include a display, which may be a graphical display depicting the welding sequence and the one or more welding parameters. The user interface may further dynamically depict a pictograph, icon or other graphical image showing how changes to the one or more welding parameters will affect the welding process, which in an exemplary manner may be the welding bead profile and/or the welding arc profile.

Abstract: A welding control apparatus according to the present invention includes an integrator for starting calculation of a voltage error integral value Sv2, expressed by a formula (1) given below, from a time when a first pulse period ends and a second pulse period starts in a pulse cycle, based on various data of information regarding a gradient Ks of an external characteristic of a welding power supply and a welding current setting value Is2 and a welding voltage setting value Vs2 both in a second pulse period, which are preset as parameters in the formula (1), as well as on an instantaneous value Io2 of a welding current and an instantaneous value Vo2 of a welding voltage both detected in the second pulse period, a comparator for comparatively determining whether a value of the voltage error integral value Sv2 provided as the calculation result has become 0, and a waveform generator for, per pulse cycle, terminating the relevant pulse cycle and starting a next pulse cycle at a time when the value of the voltage e

Abstract: A pulse arc welding method is provided for performing welding by causing welding current to flow through a welding wire and a base metal via a power supply tip. The welding current has a pulse cycle made up of a first peak time, a second peak time and a base time. A first peak current is applied during the first peak time, a second peak current, smaller than the first peak current, is applied during the second peak time, and a base current is applied during the base time. When a tip-base distance between an end of the power supply tip and the base metal is smaller or greater than a reference value, the first peak current is increased or decreased in accordance with the difference between the reference value and the tip-base distance.

Abstract: An electric arc welding device for performing a pulse welding process by a current between an advancing electrode and workpiece where the welder comprises a short detecting circuit for creating a short signal upon occurrence of a short circuit between the advancing electrode and the workpiece and a boost circuit to create a plasma boost pulse after the short circuit is cleared during the time period when the welder is not outputting the peak pulse current. The peak pulse current to background current ratio is high and the duration of the peak pulse is short.

Abstract: A superimposed voltage waveform with a predetermined cycle and amplitude is superimposed on a commanded voltage waveform for a second predetermined time after a first predetermined time elapses within an arcing period in which an arc is produced. The predetermined cycle of the superimposed voltage waveform is shorter than a short-circuit cycle and longer than a control cycle of a welding power supply unit. This suppresses a growth of a weld droplet by being pushed up toward a consumable electrode and suppresses an excessive growth of the droplet over an entire range from a low current range, characterized by frequent short-circuits, to a medium to high current range where short-circuits are less frequent. The droplet is also smoothly transferred to the weld pool in addition to preventing excessive droplet growth. This reduces the generation of spatter, giving a flatter bead appearance.

Abstract: A control method for AC pulse arc welding performed upon application of cyclic AC welding current is provided. The welding current has a cycle including an electrode negative polarity period and an electrode positive polarity period subsequent to the electrode negative polarity period. In the control method, an electrode negative polarity base current and a subsequent electrode negative polarity peak current are applied during the electrode negative polarity period. The electrode negative polarity base current has an absolute value smaller than a first critical value, and the electrode negative polarity peak current has an absolute value greater than the first critical value. Then, an electrode positive polarity peak current is applied during the electrode positive polarity period. The electrode positive polarity peak current has a value greater than a second critical value.

Abstract: The invention relates to a method for the contactless ignition of a welding arc, in addition to a circuit (28) for the contactless ignition of an electric arc, comprising a charging circuit (31), at least one pulse capacitor (30), a decharging circuit containing a circuit, and a high tension converter (32) which is used to inject the high frequency ignition pulses discharged by the pulse capacitor (30) via the circuit to the welding electrode (27). In order to create said type of ignition method and an ignition circuit (28) which enables the welding arc to be ignited in an exact and/or safe and rapid manner and/or to create an improved ignition quality, the charge circuit (31) is connected to a pulse compression circuit (40) comprising the pulse capacitor (30), the high tension converter (32) and the circuit, the circuit being formed by a magnetic throttle valve (41), such that a high frequency circuit of the ignition pulse can be obtained.

Abstract: The present invention refers to a control method and welding equipment for MIG/MAG-welding with presence of short-circuiting droplets between an electrode end and a workpiece. The method comprises establishment of a short-circuiting time, establishment of an arc time, and controlling the energy supplied to the electrode. The energy supply is controlled in such a way that the energy supply is increased if a measured short-circuiting time of a total period time, where the period time is the sum of the short-circuiting time and the arc time, exceeds a defined adjustable set value and decreases if said short-circuiting percentage goes below said set value.

Abstract: An arc welding control method for repeating alternately a short circuit period allowing a welding wire to short circuit with respect to a member to be welded and an arc period allowing arc recurrence and arc discharge to thereby weld the member to be welded, in which a welding output current just after arc recurrence is controlled to be higher than a welding output current just before arc recurrence for a set given period.

Abstract: A generator for arc welder, of the type composed of a rectifier stage followed by a PFC stage and by an inverter stage, both of the high-frequency type, the latter stage supplying power to a final rectifier stage for a welding arc, the PFC stage being composed of two inductors that are mutually magnetically coupled, two diodes with opposite conduction directions, two leveling capacitors and means for controlling the succession of the on and off switchings of the two first switches, so as to shape the current absorbed by the rectifier stage by correlating it to the waveform of the line voltage. The inverter stage comprises four triads of second controlled switches, diodes and capacitors, and there is also a control device for the four second switches and for the current for the final stage that supplies power to the welding arc.

Abstract: A contact tip for a welding gun having a central passage for a welding wire moving in a given direction toward a workpiece and receiving a welding signal by contact of the wire with the tip. The passage has an innermost end, an outermost exit end and a length of at least 1.5 inches and an opening in the contact tip intersects the passage so a pressure block slidably mounted in the opening is biased toward the wire by a spring around the contact tip urging the block against the wire. This tip is dimensioned and constructed to perform pulse welding by a relatively ductile aluminum wire.

Abstract: The invention relates to a short-arc welding method and apparatus. According to the method, an electrically periodically changing arc, which is short-circuited periodically by a molten droplet (22) from the welding wire (21), is formed between the welding wire (21) and the base material (20), in which case each welding cycle is formed of a short-circuit stage (14) and an arc stage (15), whereby both the short-circuit (12, 14) and the arc (15) stages includes both a high-current pulse (5, 10) and lower-current periods (2, 7, 12, 16). According to the invention, at the end part of each short-circuit stage (14) a falling current shape (6, 7) is formed.

Abstract: Disclosed here is a pulse welding control method and a pulse arc welding device capable of improving arc stability, and decreasing the amount of spatters. The structure contains arc short-circuit judging section (13) for judging a welding state; setting section (21) for defining parameters used for a short-circuit period and an arc period; secondary control section (25); and driving section (18). Secondary control section (25) sharply decreases welding current on detecting a moment when the tip of a wire has a neck just before recovery from the short circuit, according to at least any one of outputs from a welding current value detector, a welding voltage value detector, and the setting section. Driving section (18) selects from outputs of a pulse-waveform circuit section and a dip-waveform circuit section according to the signal from the setting section and the output from the arc short-circuit section, and outputs the selected data to a switching element.

Abstract: A system and method for operating an welding-based power source includes an welding-type power source includes a power conditioner configured to receive power from a power source and condition the power to have characteristics within a predefined set of thresholds and an inverter configured to receive the conditioned power from the power conditioner and convert the conditioned power to AC power. The welding-type power source also includes a rectifier configured to convert the AC power to DC welding-type power to drive a welding-type process and a processor segregated into at least two functional modules. The processor may be a field programmable gate array (FPGA) based processor. A first functional module is configured to control the power conditioner to condition the power to have characteristics within the predefined set of thresholds and a second functional module is configured to control the inverter to convert the conditioned power to AC power.

Abstract: Welders and methods are presented for short-circuit arc welding a workpiece using a modified series arc welding configuration with two electrodes via a sequence of welding cycles, in which each cycle includes an arc condition a short-circuit condition, wherein one or both electrode currents are selectively reversed during a reverse boost portion of the welding cycle to transfer molten metal from the second electrode to the first electrode prior to a short-circuit condition of a subsequent welding cycle.

Abstract: In pulse arc welding, a welding wire is fed at a rate corresponding to a current average set value. An arc is struck by passing a peak current for a peak period and a base current for a base period, where the peak and base periods make one pulse period. The arc transfers a droplet from the wire. The peak period includes a first peak period for a first peak current and a second peak period for a smaller second peak current. The first peak period and current are determined so that an arc anode point is formed at the top of the droplet even if the shield gas mixing ratio deviates from a standard value. The second peak period and current are determined so that one droplet is transferred during every pulse period, and beads are formed with no undercuts.

Abstract: A wire feeding speed is decreased to a level lower than a base wire feeding speed in a short-circuiting period, and set to the base wire feeding speed in an arcing period. During the arcing period, a welding current is increased to a predetermined peak value by means of current control from the start of arcing to a first predetermined time, the welding current is then supplied with a welding voltage, a source voltage of which is controlled constant, from the first predetermined time to a second predetermined time, and the welding current is decreased to a predetermined base current by means of current control from the second predetermined time until the end of the arcing period.

Abstract: Provided is a welding system and method for controlling a welding system with an improved pulsed waveform suitable for use with metal core welding wires. The waveform includes peak pulses (of voltage, current, power, energy or a combination thereof) that aid in transfer of molten metal from the wire to the weld pool. The pulse duration is sufficiently short to avoid damage to the metal core welding wire. The waveform enables welding of thin metals and reduces spatter.

Abstract: The invention relates to a method for the tandem welding of a workpiece with at least two fusible electrodes A and B to which different potentials are applied, wherein between electrode A and workpiece an impulse arc A and between electrode B and workpiece an impulse arc B burns and wherein the impulse arc A has at least one basic and one impulse current phase A with the frequency A and the impulse arc B has at least one basic and one impulse current phase B with the frequency B. According to the invention the frequency B is an integral multiple of the frequency A, while the impulse current phase A and the impulse current phase B do not overlap.

Abstract: The invention provides a welding system capable of freely controlling the dispersion and concentration of arc heat over the groove face with an extremely narrow gap and a high strength and high quality welded joint structure which is formed by this welding system and which is capable of preventing softening/hardening of the structure, the lowering of the toughness thereof and the generation of a crack. According to the welding system, the melting rate of a welding wire is controlled relative to the welding wire feeding rate by changing the characteristic of an arc current so that the range of behavior and the transfer rate of the arc pole (the arc generating main point at a groove surface) are controlled. Further, the welded joint structure consists of a high strength steel having a superfine grain structure with a carbon equivalent of as low as less than 0.

Abstract: A method and apparatus for multi process welding includes providing a controlled short circuit output and a pulse output in response to a user selection across a workpiece output stud and a torch output stud.

Abstract: An electric arc welding system for creating a first AC welding arc with a first current waveform between a first electrode and a workpiece by a first power supply and a second AC welding arc with a second current waveform between a second electrode and a workpiece by a second power supply as the first and second electrodes are moved in unison along a welding path, where the first and second power supply each comprising a high speed switching inverter creating its waveform by a number of current pulses occurring at a frequency of at least 18 kHz with the magnitude of each current pulse controlled by a wave shaper and the polarity of the waveforms is controlled by a signal. The first AC waveform has a positive portion substantially different in energy than its negative portion and/or has either a different shape and/or a synthesized sinusoidal portion.

Abstract: A method and apparatus of forming a root bead in a gap between spaced ends of at least one workpiece. The gap includes an open root. A metal cored electrode having a metal sheath and core materials is used to for the root bead in the open root. The core materials include little or no flux agents. The metal cored electrode is advanced at a given wire feed rate toward the open root to weld the ends together by at least partially filling the open root in a first weld pass. A welding current having a controlled waveform is used. The waveform includes a succession of welding cycles each having a short circuit portion and a metal the metal cored electrode and to cause the metal cored electrode to melt and transfer to the ends in the open root to form a root bead. The formed root bead has little or no slag on the upper surface of the root bead. A shielding gas is used to at least partially protect the molten metal in the open root from the atmosphere.

Abstract: An auxiliary OCV boost circuit for the power source of an electric arc welder to perform a welding process between an electrode and a workpiece, which power source has a main positive voltage output with a first voltage and a main negative voltage output with a second voltage. The boost circuit comprises a source of positive boost voltage substantially greater than the first voltage, a first switch to add the positive boost voltage to the main positive voltage, a source of negative boost voltage substantially greater than the second voltage, a second switch to add the negative boot voltage to the main negative voltage and a switch control device activated to selectively enable the first and second switches. This OCV boost circuit can be selectively operated in DC mode wherein only the main and boost voltages of one polarity is implemented.

Abstract: An electric arc welder for creating a succession of AC waveforms between an electrode and workpiece by a power source comprising an high frequency switching device for creating individual waveforms in the succession of waveforms. Each of the individual waveforms has a profile determined by the magnitude of each of a large number of short current pulses generated at a frequency of at least 18 kHz by a pulse width modulator with the magnitude of the current pulses controlled by a wave shaper. The welder is provided with a profile control network for setting more than one profile parameter selected from the class consisting of frequency, duty cycle, up ramp rate and down ramp rate and a magnitude circuit for adjusting the waveform profile to set total current, voltage and/or power.

Abstract: A method and apparatus for controlling a welding-type power supply includes providing a current wave form having an arc current portion and a short circuit current portion. An arc state is entered by retracting a welding wire, and a short circuit state is entered by advancing the wire. The current enters the arc current portion prior to the creation of the arc and the current enters the short circuit current portion prior to the creation of the short, by coordinating the wave form with the wire retraction. This may be preformed on a wire having a diameter of 2.4 mm or more to a weld and applying a welding current of less than 100 amps, or of less than 35 amps. One current waveform during the arc state includes at least three segments, and the last segment is entered into prior to the short circuit state being entered, and is the same current magnitude as the current magnitude at the start of the short circuit state.

Abstract: A method for the orbital welding of tubular elements held in abutment comprising the steps of striking an arc at a strike point with an orbital welder between an electrode and a seam formed by a first tubular element and a second tubular element, held in abutment within a fixture; initiating an orbit of said electrode around an abutment of said first tubular element and said second tubular element; adjusting the current of said arc in a pulsed manner from a maximum current to a minimum current at a set frequency, combination of said maximum current and said minimum current forming an average current; decreasing said average current in a generally continuous manner as said orbit of said electrode progresses from said strike point, the rate of decrease of said maximum current having a generally inverse relationship to the rate of increase in temperature experienced by said tubular elements.

Abstract: A method and apparatus for MIG welding is disclosed. When in an ac mode the output is unbalanced, or the balance may be controlled. The balance may be controlled to provide a desired deposition rate and /or to obtain a desired dilution. The frequency may be any frequency, for example 30 Hz, 60 Hz, 90 Hz, or more. The weld path may have groove with angle of less than 50 degrees. A consumable, cored, wire may be used, and provide at rates of 30 or 35 pounds per hour using a single arc. In various embodiments the balance may have a negative portion of at least 1.5 times the positive portion. The process may be started using an extended negative portion, for example 0.5 or 0.75 seconds.

Abstract: An electric arc welder for performing a pulse welding process by a current between an advancing electrode and workpiece where the welder comprises a short detecting circuit for creating a short signal upon occurrence of a short circuit between the advancing electrode and the workpiece and a boost circuit to create a plasma boost pulse after the short circuit is cleared during the time period when the welder is not outputting the peak pulse current.

Abstract: A method of impulse treatment which modifies at least one specified property of a material or object (such as a welded joint), or produces a material or object with at least one specified physical, mechanical or structural property, by adaptively controlling an impulse action upon the material/object is described. An impulse action includes normalized impulses and pauses, i.e., a controlled and adaptive alternation of periods of material condition impulse activation with periods of relaxation therebetween, wherein the pauses allow the material to recover from the impulse before the next impulse is applied to the material. The energy of the impulse actions can originate from various sources, but the method of the invention is in particular advantageous when the energy of action is initiated and delivered by ultrasonic impact, wherein the energy is applied to any suitable material so that at least one property of the material is modified or produced in order to attain a desired technical effect.

Abstract: An arc welder comprising: a rectifier circuit 2 which rectifies an alternating current 1 to a direct current; an inverter circuit 3; a transformer 4; a second rectifier circuit 5 which rectifies an output of the transformer 4 to a direct current; and a first reactor 6 which is connected to the second rectifier circuit 5. The arc welder further has a current circuit 10 which is connected in parallel to the second rectifier circuit 5 with a reactance that is larger than the reactance of the first reactor 6.

Abstract: A polarity switching control method is provided for consumable electrode AC pulse arc welding. By the method, a peak current and a base current are applied during an electrode-positive polarity period, while an electrode-negative current is applied during an electrode-negative polarity period. For performing the welding, polarity switching is performed to alternate the electrode-positive polarity period and the electrode-negative polarity period. When a consumable electrode and a base metal are in short circuit with each other, the polarity switching is performed after the short circuit is broken and an arc is generated.